Wheel-Check is a loose wheel nut indicator that can identify a loose wheel-nut with a simple visual inspection. When the wheel nuts are properly torqued to specs, the Wheel-Checks are then placed on the wheel nuts in a uniform pattern.The way the Wheel-Check system works is once a wheel nut has loosened, the Wheel-Check will become out of sequence. It will be visible when the driver does his walkaround check. They are also heat sensitive. If there is a binding brake or seized bearing the heat is transferred through the stud and nut. If temp exceeeds 248F the Wheel-Check will start to blister and distort.